Aspects of the present invention relate to integrated circuits and methods of deactivating the same. The present invention addresses the challenges associated with protecting personal privacy as RFID technology is used to tag individual products that are purchased and taken home by private citizens. For example, RFID systems are becoming widely used in the manufacturing and retail industry. Soon, an RFID tag is expected to be embedded in most retail products that are purchased. Therefore, the public is becoming concerned about the loss of personal privacy that will occur if these tags are used to track a person's location and/or personal habits. Accordingly, as the use of RFID technology becomes more widespread, many people will demand the ability and right to permanently disable or “kill” the RFID tags embedded in the products they purchase.
Neither unpackaging every product nor pulling the tag off of every item purchased provides a practical solution, especially when one who wishes to avoid having the item detected could do the same thing before the item gets to the checkout counter or other scanner. Therefore, a need is felt for a way to electronically and remotely kill the tags (e.g., if requested by the customer) after tracking the item is no longer desired (e.g., immediately after the customer has paid for the tagged products). While high-power techniques for permanently disabling electronic devices (such as blowing fuses, anti-fuses, etc.) are known, such techniques require that the device be placed into an electromagnetic field of sufficient power to disable the tag. As a result, these techniques are impractical in most RFID applications. For example, total reader transmission power is limited to 1 Watt by FCC regulations, and the RFID devices must be programmable at a distance of 10 meters or more from the reader. Practical RFID systems require that the KILL command must be executed with a tag power consumption of only about 1 microwatt. This power is considerably less than that necessary to blow a fuse, antifuse, or most other such programmable non-volatile memory devices. This is why most modern RFID tags must use EPROM or EEPROM memory technology for all wireless READ and WRITE operations.
However the current use of EPROM or EEPROM memory has also created a possible privacy problem because EPROM and EEPROM memories can be easily reset to their initial or “virgin” state using ultraviolet light, X-ray radiation, an electrical signal, or other methods known in the art. Because all current RFID tags are fully functional in the initial or “virgin” state, any of these “killed” or disabled integrated circuits/tags can be easily and remotely “resurrected.” Once an integrated circuit has been re-enabled in this manner, it can be easily, remotely and surreptitiously re-programmed, and used to track people without permission or knowledge. This may constitute an unacceptable invasion of privacy. Once this possibility becomes widely known, such “resurrectable” tags may be unacceptable to the general public. Thus, the industry will benefit from a way to permanently disable or “kill” these integrated circuits (e.g., RFID tags/devices) so that they cannot ever be reactivated by someone else.